1. Field of the Invention
This invention relates to computers systems and more particularly to providing flexible general purpose input/output capability.
2. Description of the Related Art
When personal computers first became prevalent, the system board (motherboard) included a relatively large number of discrete electronic components to provide all the logic functions required by the system. In order to reduce the number of components on the motherboard, both to provide space savings and to reduce costs, more and more of the functions of the computer system previously found in various components on the motherboard are being integrated into fewer and fewer integrated circuits. Thus, for example, chip sets, such as the Intel 430 FX or "Triton" chipset, have incorporated functions to provide support for various buses, memory control and input/output (I/O) circuitry.
However, system board designs still frequently require the use of various "glue" logic to support functions which may have been unanticipated when the chipsets were developed and/or are unique to a particular computer system being implemented.
One solution provided by chips supporting input/output functions is to provide general purpose input/output ports. For example, the National Semiconductor PC87306 Super I/O chip (Super I/O is a trademark of National Semiconductor Corporation) provides sixteen bits of general purpose input/output that can be read or written by software. Although that provides some flexibility in design, such an approach can still result in the need for "glue logic" on the motherboard. There exists a need to provide a more flexible approach to general purpose input/output functions in computer systems.